Is there just one correct way to calculate wing lift?

[mrspeedybob]

No no. He is claiming the down wash of air is the only component needed to explain lift. He ignores the Bernoulli Principle.
If the Bernoulli Principle did not contribute to lift, then there would be no reason for a cambered wing, you would simply use a plank.

The Bernoulli principle describes pressures. Pressure x Area = Force, which is the lift force.

If you consider the down wash of air then what you are mainly interested in is how much air is pushed down and how fast it is pushed down, aka, it's momentum. Except, that you are dealing with a continuous process, so it's really momentum imparted to the air per unit of time. mv/t. since v/t is acceleration mv/t=ma

So, Bernoulli gives you force, Newton gives you mass x acceleration...Drum roll please...

F=ma

 

[boneh3ad]

I don't want to take away from the fact that you are correct here, but I feel the need to point out that just because something is dimensionally correct doesn't make it the right equation.

 

[DaveC426913]

Well, I got to concede to the greater wisdom. I don't quite have my head around it, but I guess what I'm hearing is that there are multiple independent ways of envisioning lift, each of which explains it, fully, in a different way.

 

[russ_watters]

A great many things can be looked at multiple ways, depending on your personal preferences, provided input data and needed output. Indeed, Newton's third law tells us that all forces come in pairs, and that's kind of what we are looking at with the two methods here. I would say that though you can often get the correct answer two different ways, being "complete" means understanding both.

I like the pressure profile around the wing because it speaks to me and is visual. But for a helicopter, it tends to make more sense to view the issue from the momentum of the rotor downwash.

If someone wants to start from scratch though with "how much lift will this airfoil shape I just designed create?" that's a very difficult question to answer, going far beyond a simple/superficial pressure summing/momentum change.